Control a 24V proportional Solenoid valve with an UNO using PWM

Hello,
First time poster I do apologize if I posted in the wrong section.

I am trying to control Valve.

My circuit can be seen.

I am using an BUZ10 mosfet and an Ardunio UNO.

As I understand by applying a PWM with a 490Hz frequency to the mosfet I should be able to drive the proportional valve by changing the duty cycle. But it does not work, obviously I am lacking a fundamental understanding.

Please help me understand what I could do to make the valve work.

All the best
J

What is the horizontal connection emerging from the right side of the solenoid valve in your schematic? It appears to short out the rest of the circuit, resulting in the valve being permanently fully on.

I can see in the data sheet you linked to that the solenoid valve has 3 terminals, but I can't see where each terminal's function is described. Normally a solenoid would have only 2 terminals.

You should add a Flyback diode across the solenoid to protect the rest of the circuit, especially the Arduino, from damaging negative voltage spikes generated when the solenoid is switched off.

What is the horizontal connection emerging from the right side of the solenoid valve in your schematic? It appears to short out the rest of the circuit, resulting in the valve being permanently fully on.

The valve has three pins. (Saw your update on the post, you know this already.) The one you are referring to is the ground pin. Should i connect this to a separate ground?

resulting in the valve being permanently fully on.

Could it be that it is the opposite of what you are saying? Because the valve is permanently off. (closed)

You should add a Flyback diode across the solenoid to protect the rest of the circuit, especially the Arduino, from damaging negative voltage spikes generated when the solenoid is switched off.

I will add a diode. Thank you for the suggestion.

I also noticed the data sheet specifies a 900Hz PWM signal. The 490Hz signal you are using is not closed to that. Some Uno pins give a PWM signal closer to 900Hz, so maybe try one of those.

EDIT: on Uno, pins 5, 6 have a PWM frequency of 980Hz.

Show us first on your schematic how you would connect the diode. If you get it wrong, it could blow.

I also noticed the data sheet specifies a 900Hz PWM signal. The 490Hz signal you are using is not closed to that. Some Uno pins give a PWM signal closer to 900Hz, so maybe try one of those.

EDIT: on Uno, pins 5, 6 have a PWM frequency of 980Hz.

Thank you greatly for the suggestion. This has been tried without success.
It is a bit strange that the datasheet says one frequency and the valve says another.

Definitely need to understand what the other 2 terminals functions are before we can figure out how to control this thing. Like I said, normally only 2 terminals on a solenoid.

More than strange, it's an error, or the wrong data sheet!

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Definitely need to understand what the other 2 terminals functions are before we can figure out how to control this thing. Like I said, normally only 2 terminals on a solenoid.

The manufacturer recommends one to buy a plug with the valve. (Maybe I should just do it and maybe the problem is solved.) Plug In the end of the datasheet we can see some schematics, could these be off some help?

All the best
J

Show us first on your schematic how you would connect the diode. If you get it wrong, it could blow.

Again, Thank you for the suggestion! Is this what you meant by across the solenoid (valve).

Is the BUZ10 a logic level N channel MOSFET? It looked like a conventional MOSFET that needs a higher Vgs than the 5 volt available.

Yes, that's what I meant. But that's how you would connect a diode on a 2 terminal solenoid. With your solenoid, it might not be the correct way.

Very confusing!

How do you know that?

Are there symbols next to the terminals? Do they look similar to this?

If so, maybe disconnect the earth terminal for testing on the bench. When installed, I think it should be connected to AC mains earth for safety.

If these are the correct connections, connect pin 1 to +24V and pin 2 to the MOSFET. Wire the diode as you described.

Is the BUZ10 a logic level N channel MOSFET? It looked like a conventional MOSFET that needs a higher Vgs than the 5 volt available.

Thank you for the suggestion, according to the datasheet of the BUZ10 it is indeed a logic level MOSFET.

Kind regards
J

Thank you for taking the time to help me out.

Unfortunately, the only pin that has a symbol is the ground pin. The other two are still a mystery.

Is it still advisable to try disconnecting the ground?

All the best
J

This may be because you killed the MOSFET already.

You can find out more by connecting the power supply to the right pins, then reverse the polarity. If the valve goes on and off only by reversing polarity then you need a H-bridge to control the valve. Otherwise you have found out the polarity required to operate the valve.

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Okey, my mistake fiddling with a tablet.

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The data sheet makes the control sound more like a servo.

Have you got this piped up to a pressure supply in the right range - the pneumatic side uses a pilot valve to operate the main valve - if it’s not piped up it won’t operate .

The valve will normally closed and the sticky in the side says 400-500 Hz PWM .
Swap the valve for a led and resistor and check you can alter the brightness.
It might be useful to see your code too

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Did you size the MOSFET and 24 volt power for the 750ma maximum current needed to operate the valve?